1. Field of the Invention
This invention relates generally to bulk material belt conveyor systems. More specifically, this invention pertains to wear liners that are mounted to skirts to prevent the spillage of bulk material from conveyor belt systems and prevent the bulk material from abrading the skirts.
2. General Background Technology
All bulk material belt conveyor systems comprise a belt that extends in a continuous loop around rollers. The upper portion of the continuous loop can be referred to as a transfer run and the lower portion of the continuous loop can be referred to as a return run. Bulk material is loaded onto the belt at one or more loading zones along the transfer run. At a loading zone, it is common to provide a chute that directs bulk material onto the belt. To maximize the efficiency of conveyor belts systems, it is also common to heap the bulk material near the centerline of the belt, while keeping such bulk material from spilling off of the belt. To prevent such spillage, most chutes comprise rigid skirts that extend downward toward the belt for purposes of redirecting stray bulk material and maintaining such material on the belt. The skirts often continue for some distance downstream of the chute to provide time for the bulk material to come to rest relative to the belt. Skirts may also be provided along other portions of the transfer run to reposition bulk material that has migrated toward the sides of the belt. Because many types of bulk materials are abrasive, it is also common practice to attach wear liners to the skirts, which prevent the skirts from direct contact with the bulk material. In contrast, the wear liners do wear from direct contact with the moving bulk material and periodically must be replaced. However, such wear is expected. In addition to replacement, it is also often desirable to be able to periodically adjust the position of the lower edge of the wear liners relative to the skirt and belt. By doing so, a desired gap between the wear liners and the belt can be generally maintained. The positioning of the wear liner is critical to controlling spillage and incorrect or inadequate mounting can cause severe damage to the belt.
It is common practice to mount the wear liners on face of the skirt that faces the centerline or center plane of the belt. Since the cross section of the belt is often trough-shaped, it is also common for the lower edge of a wear liner to be positioned lower than the lower edge of skirt so as to reduce the gap between the lower edge of the wear liner and the belt. Still further, belt seals are often attached to the side of the skirt that faces away from the center plane of the belt. Such belt seals engage the belt and prevent dust and fine bulk material from spilling off of the belt.
Due to the fact that wear liners are mounted to the side of the skirt facing the center plane of the belt (the inward side), it is often necessary for a worker to climb into a chute or onto the belt to replace worn wear liners. Following confined space procedures and working in very difficult conditions make it difficult to accurately position the wear liners. However, others have developed apparatus and methods that allow such wear liners to be replaced from the opposite side of a skirt (the outward facing side). For example, Nelson Williams Linings, Inc. manufactures a skirt that has portion that can be pivoted in a manner that allows a portion of the inward facing side of the skirt to be tilted to the point wear it faces upwards. This allows wear liners attached to the pivoting portion to be replaced from the outward side of the skirt and is describe in U.S. Pat. No. 6,763,935. However, such techniques create new safety issues, make it difficult to seal between sections of wear liners, make inspection of the mounting with the belt loaded impossible, and impact the structure of the skirts, which must bare the loads associated with diverting the bulk material.